Understanding 24-hour movement behaviours and their associations with children’s psychosocial health during the transition from primary to secondary school

Background The transition from primary to secondary school is one of the life transition periods during which significant behavioural changes may occur. However, there is little evidence on concurrent changes in sleep, sedentary behaviour and physical activity (PA) (collectively known as 24-hour movement behaviours) over a 24-hour period during this school transition period. Further, the combined associations between time spent in 24-hour movement behaviours and psychosocial health are still under-researched in children. This information may inform the development of future movement behaviour intervention strategies and guidelines to assist children in making a healthy transition to secondary school. The overall aim of this doctoral thesis was to explore changes in 24-hour movement behaviours and their associations with children’s psychosocial health over the transition from primary to secondary school. Methods This thesis is comprised of four research papers, one of which is a systematic literature review and the other three are original research studies using data from two longitudinal surveys. The first and third studies analysed primary data from a longitudinal school-based survey that followed a cohort of children in New South Wales, Australia from their final year of primary school (Year-6; aged 10-12y) to their first year of secondary school (Year-7; aged 11-13y). The second study used national data from Waves 4 (2010) and 5 (2012) of the Longitudinal Study of Australia Children (Kindergarten cohort) when participants were in primary (aged 10-11y) and secondary school (aged 12-13y), respectively. Results The systematic literature review identified five articles that reported only changes in PA, while one reported changes in both PA and sedentary behaviour during the school transition period. There were no studies that examined changes in sleep duration or changes in all three movement behaviours concurrently. The first study (n=83) investigated changes in the accelerometer-measured 24-hour movement behaviour composition and adherence to the Australian 24-Hour Movement Guidelines during the school transition period. An unfavourable change was observed in the movement behaviour composition, with increased time spent sedentary and decreased time in sleep and PA. The change in the weekday movement behaviour composition was significantly more prominent compared to that of the weekend. Furthermore, there was a substantial decrease in the proportion of children meeting the integrated 24-hour movement guidelines (i.e., from 20.5% to 3.6%). The second study (n=909) investigated changes in the domain-specific movement behaviour composition as measured by a single-day time-use diary (67.4% school day; 32.6% non-school day), and explored whether these changes were associated with changes in children’s psychosocial health during this transition period. A more drastic change in movement behaviour composition was observed among the school day sample compared to the non-school day sample. Furthermore, the change in movement behaviour composition was significantly related to changes in prosocial behaviour among boys. Specifically, increased time spent in social activities and recreational screen use (relative to other activity domains) were associated with decreased prosocial behaviour. There were no significant associations between the change in movement behaviour composition and the changes in psychosocial health among girls. The third study examined the cross-sectional (n=127) and longitudinal associations (n=88) between 24-hour movement behaviour composition, recreational screen use and children’s psychosocial health. The movement behaviour composition and recreational screen use levels were independently associated with psychosocial health outcomes cross-sectionally but not longitudinally. Relative to other behaviours, more time spent in sleep and less time spent in light-intensity PA were associated with lower levels of internalising problems and total psychosocial difficulties. Conversely, higher sedentary time was associated with greater internalising problems. High levels of recreational screen use (\u3e2 h/day) were associated with greater externalising problems, total psychosocial difficulties and psychological distress. Conclusion This thesis has provided new evidence to advance the understanding of children’s 24-hour movement behaviours and their combined associations with psychosocial health during the transition from primary to secondary school. It is recommended that an integrated intervention approach addressing the full composition of 24-hour movement behaviours be adopted to effectively improve children’s movement behaviour profiles during this transition period. Future research should also continue to measure and analyse both intensity- and domain-specific movement behaviour compositions given the differing associations noted with children’s psychosocial health

24 hour movement behaviours and the health and development of pre-school children from Zimbabwean settings: the SUNRISE pilot study

Background: In 2019, the World Health Organization (WHO) released global guidelines for physical activity, sedentary behaviour and sleep for the early years. The International Study of Movement Behaviours in the Early Years, SUNRISE, aimed to assess the extent to which children aged three and four years meet the WHO global guidelines and its association with health and development. Objectives: To assess movement behaviours in pre-school children from low-income settings in Zimbabwe and to establish associations between these movement behaviours and adiposity, motor skills and executive function.Methods: Pre-school children/caregivers were recruited from two urban and two rural public schools respectively in Zimbabwe. The caregivers answered questions on the children’s physical activity, screen time, sedentary behaviour and sleep patterns. Children’s movement behaviours were objectively measured using accelerometers. Gross and fine motor skills and executive function were assessed using the Ages and Stages Questionnaire-3 and Early Years Toolbox, respectively. Focus group discussions were carried out with caregivers and teachers on the acceptability and feasibility of the study. Results: Eighty-one children participated in the study. The proportions of children meeting the guidelines were physical activity 92%, sedentary behaviour 70%, and sleep 86%, and all guidelines combined 24%. Boys and girls were similar (p>0.05 for all variables) for all executive function variables, but rural children had significantly lower inhibition scores (p=0.026) than urban children. Conclusion: The study adds to the growing literature on movement behaviours and associated risk factors in low-resourced settings. Further investigations of movement behaviours in this age group in Zimbabwe are recommended

Validity of low-cost measures for global surveillance of physical activity in pre-school children : the SUNRISE validation study

Objective: To validate parent-reported child's habitual total physical activity (TPA) against accelerometry and three existing step-count thresholds for classifying 3 h/day of TPA in pre-schoolers from 13 culturally and geographically diverse countries. Design: Cross-sectional validation study. Methods: We used data involving 3- and 4-year-olds from 13 middle- and high-income countries who participated in the SUNRISE study. We used Spearman's rank-order correlation, Bland-Altman plots, and Kappa statistics to assess correlation and classification ability of parent-reported child's habitual TPA against activPAL™-measured TPA over 3 days. Additionally, we used Receiver Operating Characteristic Area Under the Curve (ROC-AUC) analysis to validate three existing step-count thresholds (Gabel, Vale, and De Craemer) for accurately classifying achievement of the WHO guideline of at least 3 h/day TPA using step-counts derived from activPAL™. Results: Of the 352 pre-schoolers, 49.1 % were girls. There was a very weak but significant positive correlation and slight agreement between parent-reported and accelerometer-measured TPA (r: 0.140; p = 0.009; Kappa: 0.030). Parents over-estimated their child's TPA compared to accelerometer data (mean bias: 69 min/day; standard deviation: 126; 95 % limits of agreement: −179, 316). Of the three step-count thresholds tested, the De Craemer step-count threshold of 11,500 steps/day provided excellent classification of meeting the TPA guideline as measured by accelerometry (AUC: 0.945; 95 % CI: 0.928, 0.961; Sensitivity: 100.0 %; Specificity: 88.9 %). Conclusions: Parent reports may have limited validity for assessing pre-schooler's level of TPA. Step-counting is a promising alternative – low-cost global surveillance initiatives could potentially use pedometers for assessing compliance with the physical activity guideline in early childhood

Cross-sectional examination of 24-hour movement behaviours among 3-and 4-year-old children in urban and rural settings in low-income, middle-income and high-income countries : the SUNRISE study protocol

Introduction 24-hour movement behaviours (physical activity, sedentary behaviour and sleep) during the early years are associated with health and developmental outcomes, prompting the WHO to develop Global guidelines for physical activity, sedentary behaviour and sleep for children under 5 years of age. Prevalence data on 24-hour movement behaviours is lacking, particularly in low-income and middle-income countries (LMICs). This paper describes the development of the SUNRISE International Study of Movement Behaviours in the Early Years protocol, designed to address this gap. Methods and analysis SUNRISE is the first international cross-sectional study that aims to determine the proportion of 3- and 4-year-old children who meet the WHO Global guidelines. The study will assess if proportions differ by gender, urban/rural location and/or socioeconomic status. Executive function, motor skills and adiposity will be assessed and potential correlates of 24-hour movement behaviours examined. Pilot research from 24 countries (14 LMICs) informed the study design and protocol. Data are collected locally by research staff from partnering institutions who are trained throughout the research process. Piloting of all measures to determine protocol acceptability and feasibility was interrupted by COVID-19 but is nearing completion. At the time of publication 41 countries are participating in the SUNRISE study. Ethics and dissemination The SUNRISE protocol has received ethics approved from the University of Wollongong, Australia, and in each country by the applicable ethics committees. Approval is also sought from any relevant government departments or organisations. The results will inform global efforts to prevent childhood obesity and ensure young children reach their health and developmental potential. Findings on the correlates of movement behaviours can guide future interventions to improve the movement behaviours in culturally specific ways. Study findings will be disseminated via publications, conference presentations and may contribute to the development of local guidelines and public health interventions.Peer reviewe

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Physical Activity Promotion in Malaysia: Challenges and Opportunities

Copyright 2020 Khoo, Poh, Suhaimi, Chong and Ramirez Varela. About three quarters of the Malaysian adult population are physically active. There has been growth in physical activity and health research since 2010, with most studies being observational in design and few included objective measures of physical activity. The Malaysian Ministry of Health has published physical activity guidelines, strategies and action plans aimed at promoting physical activity. Physical activity promotion activities have included national campaigns and programmes which target different populations. Further work that incorporates the WHO Global Action Plans on Physical Activity (GAPPA), as well as a more systemic approach is needed, to promote physical activity and a healthy lifestyle. High-level multi-stakeholder collaboration is required for continuing expansion and strengthening of research capacity, and for bridging the physical activity policy gaps in Malaysia

Longitudinal changes in domains of physical activity during childhood and adolescence: A systematic review

Objectives: Physical activity (PA) participation is prone to decline during adolescence. An understanding of the domains of PA that are susceptible to decline may support a more targeted approach to PA and health promotion. The aim of this study was to review longitudinal trends in participation in four PA domains during childhood and adolescence: organized PA, non-organized PA, active transport and active chores. Design: Systematic review. Methods: 5517 research articles were sourced from five electronic databases (covering January 1997-April 2018). Eligibility criteria included repeated measurements of at least one PA domain among the same participants (5-18 years of age). Results: 23 studies were included, cumulatively reporting data from 27,231 participants. Few studies had a low risk of bias (n = 6). Most studies of active transport reported an increase in participation during childhood, no change in the transition to adolescence, and no change or decline during adolescence. Most studies of organized PA reported an increase during childhood, an increasing or stable pattern in the transition to adolescence, and no change or decline during adolescence. Non-organized PA participation tended to remain stable among adolescent girls and decline among adolescent boys. Active chores increased during the transition to adolescence and then stabilized. Conclusions: Potential strategies for PA promotion among youth may include targeting non-organized PA among adolescent boys or organized PA among late adolescent boys and girls. However, there is a continuing need for high-quality, longitudinal studies of participation in PA domains, particularly non-organized PA and active chores. PROSPERO Registration: CRD42017076888

Sociodemographic moderators of longitudinal changes in active play between childhood and adolescence in Australia

Physical activity (PA) participation is prone to decline during childhood and adolescence. In Australia, this decline has been shown to particularly occur in active play. This study aimed to identify sociodemographic moderators of change in active play between 10-11y and 12-13y among Australian youth. The data were sourced from Waves 6–7 of the Longitudinal Study of Australian Children (n = 3567). Active play participation was measured using one-day time-use diaries (TUDs) completed by youth. Potential sociodemographic moderators were tested using multilevel mixed modelling, adjusted for pubertal development, body mass index z-score and TUD contextual variables (school attendance and season). Active play declined more among girls (β= −7.6 min/day, 95% CI = −13.3, −1.8), those who spoke English at home (β= −12.3 min/day, 95% CI = −22.0, −2.7) and marginally among those in regional/remote areas (β= −6.3 min/day, 95% CI = −12.8, +0.1). A widening gap in active play by sex was observed, while differences by language spoken at home and geographical remoteness weakened or became marginal over time. Interventions to promote active play could target girls in the transition to adolescence. Future studies could investigate whether active play declines earlier than 10-11y among youth who speak languages other than English at home and those living in urban areas

Interventions to Change School Recess Activity Levels in Children and Adolescents: A Systematic Review and Meta-Analysis

2020, Springer Nature Switzerland AG. Background: The school environment is globally recognised as a key setting to promote child and adolescent physical activity. School recess contributes up to 40% of the school day and recommended physical activity levels, providing a critical physical activity promotion opportunity for children and adolescents. Objective: To examine the effectiveness of school recess interventions on children\u27s and adolescents\u27 physical activity (PA) and sedentary behaviour (SED) during this time. Design: Systematic review and meta-analysis. Data Sources: EBSCOhost (Academic Search Complete, Education Source, ERIC, Global Health, MEDLINE complete, SPORTDiscus), Scopus, and ProQuest electronic databases with full text. Results: Forty-three studies were included in the systematic review, trialling eight different intervention strategies including loose equipment, structured recess, and multicomponent studies. The meta-analysis included 16 studies. Overall, between group mean difference for: (i) time spent in moderate to vigorous-intensity physical activity (MVPA) for randomised controlled trials (RCTs) (n = 6) was 0.18 (95% CI − 0.00 to 0.36) with a marginal significant effect of Z = 1.93 (p = 0.05), (ii) time spent in MVPA for non-RCTs (n = 7) was 0.52 (95% CI − 0.01 to 1.03) with an overall effect of Z = 1.99 (p = 0.05), (iii) time spent in sedentary behaviour for RCTs (n = 3) was − 0.48 (95% CI − 1.38 to 0.43) with an overall effect of Z = 1.03 (p = 0.30). All outcomes had high heterogeneity. Conclusion: School recess interventions show promise for increasing MVPA. It was difficult to draw strong conclusions due to low study numbers in the meta-analysis and varied intervention designs. Interventions may need to focus on single component strategies (e.g., loose equipment) to improve understanding of outcome effects for future studies

Associations Between Device-Measured Physical Activity and Indicators of Adiposity among US Children and Youth

This project involves a secondary analysis of three cycles of NHANES data to examine dose-response associations between device-measured physical activity behavior using accelerometry and indicators of adiposity. Independent and joint effects of physical activity volume and intensity will be examined as predictors of overweight/obesity status, abdominal obesity status, BMI z-scores, and body fat percentage